The Flash #220

In "The Slowest Man on Earth," the Flash and Kid Flash face a bizarre threat when the mysterious Turtle, a man who moves at glacial pace, attempts to harness the Earth’s rotation using a cyclonic dynamo to amplify his own sluggish speed into a planetary force. When a lab accident causes the two speedsters to merge, Barry Allen and Wally West must struggle to separate and stop the Turtle before his plan spins out of control—while Iris Allen watches in stunned disbelief.